The survey of the Central Region grasslands was carried out in the autumn of 1989 following the completion of the Fife Grassland Survey, which occupied much of the occupied much of the earlier part of the year. Because of the restricted time available, complete cover of the lowland grassland communities could not be contemplated and it was agreed that field work would be limited to a number of agreed sites where information was required as a priority. An added disadvantage was the seasonal state of the vegetation, with most plants having flowered and started to die back.
Although inevitably some of the early-flowering ephemeral species would be overlooked, it was felt that most of the plants required for an assessment of the conservation value of the sites could be identified from their vegetative parts.
METHODS
Each site was visited and a number of inspections made to establish the range of communities present. Where a grassland community of potential conservation value was identified, one or more quadrats were recorded, otherwise only species lists were noted from vegetation of lesser importance. Data recording was carried out on special cards designed for the purpose by the Nature Conservancy Council and community boundaries were delineated on maps of either 1:10,000 or 1:15,000 scale. Records included the physical features of the site, such as altitude, aspect and slope, the underlying geology and soil ", the area of the site itself and of each component habitat type where possible. The species within each quadrat were accompanied by an assessment of their cover abundance based either on the DOMIN scale or on the DAFOR score (Dominant Abundant, Frequent, Occasional Rare). Finally, a report was prepared, with sections on the broad physical features of Central Region, on the habitat characteristics of the sites under investigation and on the assessment of the conservation value of each site. The report was accompanied by the completed record cards and maps, comprising seventeen sets in all.
PHYSICAL FEATURES
Central Region extends from Breadalbane in the north to Armadale in the south, from Ben Lui in the west to Dollar in the east. Straddling as it does the Southern Highlands, the Highland Boundary Fault and the Midland Valley, it is not surprising that the scenery is extremely varied, but even so, the area is comprised of only two major landform units - the Central Lowlands and the South-west Grampian Highlands.
The Central Lowlands - lie to the south-east of the Highland Boundary Fault and occupy the northern part of the Midland Valley of Scotland. The portion within the Region consists of the Forth Lowlands which lie mostly below 175 metres, although much ground exceeds 300 metres and the highest parts rise to almost 600 metres on the Campsie Fells. The lowlands of Stirling and Clackmannan are underlain by Carboniferous sediments which include mainly sandstones and shales, with some coals and occasional limestones and calciferous sandstones. Below these strata lie rush of Upper and Lower Old Red Sandstone age, and basal conglomerates of these formations form the hilly ground east of Callander, where the hardness of the rock resists erosion. During the deposition of these Carboniferous and Old Red Sandstone sediments and in the ensuing Permian era, considerable volcanic activity took place and resulted in the formation of intrusive igneous rocks such as the Gargunnock Hills - a vast sequence of basaltic lava flows which form the northern tip of the Campsie Fells plateau.
Three distinct phases of glaciation have been identified in the area, each contributing towards the variety of tills that now form the soil parent materials.